[GRASS-dev] i.fusion.hpf addon: observing strong range change

[Moritz Lennert]

On 28/10/19 12:33, Markus Neteler wrote:
> On Mon, Oct 28, 2019 at 10:46 AM Moritz Lennert
> <mlennert at club.worldonline.be> wrote:
>> On 27/10/19 18:52, Markus Neteler wrote:
>>> Hi,
>>>
>>> I am using i.fusion.hpf on Worldview-2 data and see that the resulting
>>> range is completely different:
>>>
>>> # orig
>>> r.info -r wv2_17OCT08182034_M2AS_058891334010_01_P001.5
>>> min=0
>>> max=1509
>>>
>>> # HPF
>>> r.info -r wv2_17OCT08182034_M2AS_058891334010_01_P001.5.hpf
>>> min=-1045.79783524995
>>> max=3416.06793724612
>>
>> Just guessing here, but did you try the -c flag ?
> 
> Now yes:
> 
> i.fusion.hpf pan=$PAN msx=$(g.list raster pattern="$COLORPREFIX.?"
> sep=comma) -c --o
> 
> # band 8
> r.info -r wv2_17OCT08182034_M2AS_058891334010_01_P001.8
> min=0
> max=1605
> 
> r.info -r wv2_17OCT08182034_M2AS_058891334010_01_P001.8.hpf
> min=-1163.98434592277
> max=3879.99538075697
> 
> So, -c doesn't seem to have any effect here.
> 

Sorry, wrong flag, should have been -l ("Linearly match histogram of 
Pan-sharpened output to Multi-Spectral input")

And if you rescale the output manually to the input value range, do you 
still see a good fusion result ? If yes, then this could be added as a 
last step to the module.

Moritz